1. Field of the Invention
The present invention relates to a material capable of imparting anisotropy to the thermophysical properties of the surface of a solution prepared by adding a polymer or a monomer to a solvent, which is applicable to production of optical films such as polarizers, anisotropic thermoconductive films, etc.
2. Description of the Related Art
For imparting anisotropy to a film, well employed is a photoalignment method using an azo material. For example, a method for producing a photoalignment film is disclosed (see JP-A 2005-49386), which comprises applying a photoaligning material onto a substrate and fixing it thereon with applying an anisotropic light to it. JP-A 2001-290028 discloses an example of applying the technique to optical film production.
For functional films such as optical films and the like that are required to have severe uniformity of themselves, the uniformity in coating in film formation and the uniformity in drying in the process of drying the formed film to remove the solvent through evaporation therefrom are important factors, for which, for example, employed is a method of adding a polymer that are selectively much adsorbed by the surface of a liquid film, such as a surfactant to the film-forming liquid to thereby control the physical properties of the liquid on a desired level to form a uniform film surface. For evaluating the anisotropy of a photoalignment film, for example, the change in the refractive index, the transmittance or the like of the film is optically determined.